Vibrator



Aug. 19, 1941.

H. M. DRESSEL VIBRATOR Filed Dec. 24, 1934 2 Sheets-Sheet 1 s L 5 E D M.MEY B Aug. 19, 1941. H. M. DREssEL VIBRATOR Filed Dec. 24, 1934 FIGAF1G.6. F1631.

FIGS.

b v... um wDC'Mwfwm MMHD u n N lmMWhvVA. nnbh HKE n m .awww w 4 a... mNMMH 5. OT t ).1 l A. |111 1 u XIHH.. 0 ,C.. f i-.. mm

.an w www. .9. m .nl

Patented Aug. 19, 1941 vmna'ron Henry M. Drossel, Chicago, Kenneth C.Allison, Arlington Heights, and Edward J. Maltney, Berwyn, Ill.,assignors to Oak Manufacturing Company, Chicago, Ill., a corporation ofIllinois Application December 24, 1934, Serial No. 758,924 (Ci. zoo-9o)32 Claims.

This invention relates to vibrators and more particularlyto vibratorsfor use in connection with automobile radios and the like. Vibrators forthis purpose are customarily energized from a 6 or 1,2 volt battery, andare adapted to supply an interrupted current to a. transformer. Becauseof the low voltage and the high current density, great difficulty hasbeen experienced in providing a satisfactory vibrator which willfunction at a uniform level of elcienc'y. In the past, trouble has beenexperienced at the contacts, which has resulted in a high voltage drop,thus cutting down available voltage and current for the transformer.When a device of this character begins to deteriorate, it goes from badto worse very quickly.

In vibrators where the driving contacts also.

carry the working circuit current, it is necessary to use expensivecontact material. This is because oxidation affects the contactsurfaces. With a vibrator having separate driving contacts, however, thecurrent density is low and small contacts of good material may be used.The working circuit contacts may be of inferior material since they arepositively driven by the vibrating element independently of the natureof contact established. After the first few impacts,the oxide is rubbedof! and perfect contact -is Aestablished for the work circuit. l

Furthermore, it is desirable to break the contacts in the smallest timeinterval possible to avoid arcing. Where the contacts are spring mountedand do not have any rigid abutment to give a hammer break, it has beenvery clitliI cult to obtain a quick break. Usually in such a case, mebreak occurred when the contact was near its extreme position andtraveling with low velocity. In the vibrator to be described, however,the contact is broken at the center position of the movable contactwhere the velocity is a maximum.

An object of this invention is to devise a vibrator which wili operatesatisfactorily over long periods of time. Another object is to devise astructure of this character which will be simple and cheap and whichwill operate quietly.

Referring to the-drawings, Figure 1lshows a sectional elevation of avibrator, embodying the present invention. Figure 2 shows a view of thesame vibrator in partially disassembled condi-tion and at right anglesto Figure 1. Figure 3 is a detail of the-'toprubber damping member.Figure 4 is a detailfof the bottom rubber supporting member. Figures' 5to 8, inclusive, are details of a vibrator reed. Figure 9 is a viewpartly in seci netic material, such as iron. Frame I has a bight portion2, in the center of which is mounted a pole piece 3. This piece ispreferably-narrower than frame I, as shown in Figure 2, and extendsdownwardly :toward the open arms of frame I. Pole piece 3 has a tip 4,which is oiset from the body of the pole piece, so that tip 4 iseccentric with respect to the two arms of frame I. Pole piece 3 may befastened in bight portion 2 in any manner, such as by projecting throughan aperture in bight portion, and spreading the metal on the outside.

Disposed around pole piece 3 is aA spool-5, preferably containing twowindings and connected in a manner to be later described. Frame I iscomposed of two arms, Il) and II, connected by bight portion 2. Arms I0and II, preferably have their ends, I2 and I3, bent toward each other atregions I4 and I5. Between ends I2 and I3 is clamped :the entirevibrator system.

This comprises a reed generally designed as 20 and to be described infurther detail later. Said reed carries a movable driving contact, 2I,adapted to co-operate with a fixed drivingl contact, 22, adjustablymounted on threaded portion-23 in arm I I of the frame.. Contact 22 maybe adjusted to any desired position and locked therein by means of a nut25. In addition, reed 20 carries a pair of movable contacts, 2B and 21,adapted to co-operate with fixed contacts, 28 and 29.

Reed 20 is maintained in position by having its end 30 rigidly clampedbetween a series of metal spacer plates 3i and 32. Next to 'these plates3i and 32 are disposed insulating separators 34, 35,16 and 31,preferably of mica. Between each adjacent pair of insulators, there isdisposed supporting arms 40 and 4I, carrying stationary contacts 2l and29. These arms are spring-like and have a natural frequencysubstantially higher than the natural frequency of reed 2G. Beyond theinsulators are additional metallic spacer lplates 42 and 43, adapted t`osnugly fill up the space between ends I2 and` I3 of frame I.

This entire assembly is maintained intactby means of a pair of bolts, 45and 46. Everyone of the spacers and insulators between ends I2 and I3are provided with suitable apertures through which these bolts may bethreaded. AS

shown in Figure i, these apertures are sumcient- 1y greater in diameterthan thebolts, so that a suitable insulating region may be formed, whichmay be occupied by an insulating sleeve. Bolts and 48 are provided withnuts 41, which maintain the entire assembly rigid.

Referring to reed 2U, Figure 5 shows the spring suitably punched out.Spring 28 has its bottom portion, 30, provided with the apertures and5|, previously generally described for the reception of bolts 45 and 46.Above bottom portion 30, whichis adapted to be rigidly clamped, is aprimary pivotal portion, 52. This portion preferably has a smallrectangular region, 53, punched out. As is clearly shown in Figure 5,region 53 is symmetrically located with respect to the sides of thespring and has its long dimension transverse to the spring. Above region52 is a region 55, carrying a pair of rivets, 58 and 51. 'I'hese rivetsare preferably in line with each other on a horizontal axis, and arespaced sufciently wide apart so that each rivet goes through an outerpart of the spring. Above region is a region 80, having a long centrallydisposed cutout, 6I. This cutout has preferably the same width asportion therewith. Cutout Si has its greatest length along the length oireed 2|), and has a small spring 62 therein. This spring is integralwith main spring 20 and has an enlarged rounded head, 63, carryingdriving contact 2|.

The free end B5 'of spring 20 is adapted to carry an armature, 66,riveted thereto at 61 and 68. It will be noted that rivets 61 and 68 arepreferably co-linear with 56 and 51. i

Rivets 56 and 51 are adapted to support on eachv side of spring2li-rigid arms 10 and 1|. These arms are preferably bent so as to Hareoutwardly and comprise a broad mounting region, 13, of the same width asspring 20, and a narrow contact supportingportion. These arms, 10 land1|, support movable contacts, 26 and 21. Between arms 10 and 1|, issupported a rigid arm 14 abutting against spring 62. In the normalposition of reed 20, contacts 2| and 22 are tightly closed. To preventspring 62 from maintaining the contacts in closed position as reed 20movesv away, abutment 14 moving with the main body of reed 20 carriesspring 62 with it to open the driving contacts. of any bias of spring 62tending to keep the driving contacts closed even after reed 20 hasstarted to move away, member 14 immediately opens these contacts.

As is evident from Figure l. the entire reed assembly is so supportedthat in its position of rest, driving contacts 2| and 22 are closed andarmature 66 is to one side of pole tip 4. In operation, the interactionbetween pole tip 4 and armature 66 suffices to cause the reed tovibrate. This vibration results in a fiexure at region 52 openingdriving contact 2|. By virtue of inertia, and the impact withcooperating contact 22, there is also a exure of spring 62, relative tospring 20. In addition, there is considerable exure at region 68.

1t is evident that the shapes of the cutouts in the reed are such thatno deiinite axis of ex ure across the reed is provided. The portion oi'the reed with the cutout will flex along its entire extent and while theiiexure may or may not be uniform along the reed cutout length,nevertheless there will be no sharp variation in flexing characteristicsalong the cutout length. Obviously flexing goes with stress so that anysharp Hence, in spite 53 and is located in line variation in exingcharacteristic along a reed implies a sharp stress variation.

Supporting arms 40 and 4| are preferably resilient enough so that whenany one pair of contacts are together they remain so while reed 28 istraveling toward the center position. When the center position has beenattained, the contacts separate. Arms 4|) and 4|` are stiff enough sothat their natural frequency is substantially higher than that of reed28. Hence even though one of these arms is moving towards its extremeposition, nevertheless the contact separation is quick -and sharp.

The various contact carrying members are provided with soldering lugs,15, to which may be soldered suitable wires. These wires arethreadedthrough small flexible rubber tubes, 11, oi' a resilientmounting, 18. This mounting comprises a soft rubber member, having arectangular cup-shaped portion, 80, adapted to enclose the bottom of thevibrator unit. The bottom of cupshaped portion has formed thereon aflange, 8|, having a projecting rim, 82, surrounding tubes 11. The wiresthreaded through tubes 11 are preferably soldered to the prongs 85,rigidly mounted in a disk, 88, of hard insulating material. `This diskhas a circular configuration of approximately the dimensions of rim 82with the exception of a projection 83. Above this projection is asoldering lug 84 riveted to one of the prongs 85 and in practiceconnected to the ground wire. As shown in Figure,9, when the vibrator isput into can 81, insulating disc 86 is cocked to permit -lug 84 andprojection 83 to project through an aperture in can 81.

A metal can, 81, is provided at its open end with alcircularconstriction, 88, and thereafter with an annular region, 89, terminatingin a lip, 9U. As is evident in Figure 1, portion 82 is adapted to bejammed under constrictionv 88. Insulating disk 86 is forced againstconstriction 88 to jam the rubber in place and the entire assembly ismaintained by means of a spring ring, 9|. Projection 83 and lug 84passing through an aperture in can 81 lock the vibrator against turningrelatively to can 81. Lug 84 is bent up against can 81 and solderedthereto to ground can 81.

As shown in Figures 1 and 9, when the vibrator is in position inside ofcan 81, and above insulating base 86, the rubber tubes 11, are distortedfrom their natural straight position into a bent position. By virtue ofthe compressing of the rubber tubes and the outer ilange 82, the entireassembly is maintained intact in a flexible, but rm, manner.

To prevent excessive displacement of the top end of the vibratorstructure, there is preferably disposed a soft rubber cap, |00, over`the top of the vibrator assembly. This cap has a downwardly extendingflange lili, which is adapted to lie along the top portion of thevibrator structure and two wing portions, |82 and |03, extend ing fromopposite sides, and perpendicular to the line of motion of the reed,adapted to clear the inside of can 81. This entire rubber assembly has arectangular cross section as shown in Figure 3 for snugly tting over thetop end oi' the vibrator and while permitting a certain degree ofmotion, nevertheless tend to dampen the vibration of the structure andprevent contact with the metal can. This is particularly positioned asshown. This vibrator mounting is claimed in our divisional application,now Patent No. 2,140,792.

true with the cap 'v Rectifier contacts y through leads 256 and 251 tothe ends of the In Figure 8 is shown a modified form of reed for acombined interrupter and rectifier. In this construction, the contactmounting portion |13 has offset arms on each side thereof, as in Figure6, only one being shown. Each contact bearing`portion carries twocontacts, |26 and 226. This is adapted to co-operate with a set ofstationary contacts |28 and 228, s hown in Figure 9, each of thesecontacts being carried on separate supporting members, |4| and 24|.These contact bearing arms are in general similar to the contact bearingarms 40 and 4| of Figure 1, and are supported in the same manner.

Referring to Figure 10, magnetizable member carries two coils |50 and|5| both wound together. Coil |56 has its terminals connected togetherto reduce the self induced potentials and currents in coil |5| and thuscut down arcing at driving contacts 2| and 22. This is more fullydescribed and claimed in Dressel Patent No. 2,012,123. Coil |5| lhas oneterminal connected to fixed driving contact 2|. The other terminal isconnected by lead |52 to terminal |53 of a battery. The other terminall|54 of the battery is connected to reed 52 through a suitable switch v|55. Fixed contact 26 and 26 are connected through leads |56 and |51 tothe ends of a transformer primary, |56. The midpoint of primary |56 isconnected to terminal |53 of the battery. |26 and |28 are connectedtransformer secondary 258. The center of the secondary is brought out asa terminal 259 while another terminal 260 is connected to reed 52 tosupply rectified pulsating currents. It is understood of course that inpractice, leads 256 and 251 may have to be interchanged 'to obtain thecorrect polarity.

Having described this invention, what is claimed is:

1. A vibrator comprising a U-shaped member of magnetizable material, apole piece disposed in the bight of said' U, a magnetizing coil for saidpole piece, a spring reed supported at the open end of said U and havingan armature in co-operative relationship to said pole piece, astationary contact carried by said U-shaped member in proximity to saidreed, said reed having an elongated portion thereof cut out to leave asmall spring armintegral with said reed exf tending upwardly toward thearmature end and having the free end of said small spring adjacent saidstationary contact, and a movable contact carried by said small springand connected with said magnetizing coil for driving the vibrator,

2. A vibrator comprising an elongated magnetizable member having a polepiece, a magnetizing coil for said member and pole piece, a spring reedhaving one end rigidly supported on said member and having the otherfree end disposed adjacent said pole piece, an armature carried by thefree end of said reed and adapted to vibrate said reed under theinfluence of a fluctuating magnetic field, a stationary contact carriedby said member, said reed having an elongated region adjacent the freeend thereof wherein the material is cut out to leave a small springmember integral with said reed and extending toward the free end thereofwithin said region, a contact carried by the free end of said smallspring and adapted to co-operate with said stationary contact,connections with said magnetizing vcoil and said contacts, whereby saidreed is vibrated upon suitable energization of said coil, aI pair ofstationary contacts, one on each side of said reed carried by saidmember and symmetrically disposed with respect to said reed, and a pairof co-operating movable contacts carried by said reed for controlling acircuit, said additional movable contacts being mounted on oppositesides of the reed and carried by a portion of the reed located outsideof saidfcutout4 region.

3. A vibrator comprising an elongated U- shaped magnetizable memberhaving a pole piece at the bight thereof, and a magnetizing coiladjacent the pole piece, a reed supported at the open end of said U, andcarrying an armature `at the free end thereof and adapted to vibrate inproximity to said pole piece, a stationary contact carried by saidU-shaped member, said reed having an elongated cutout with the length ofthe cutout in line with the length of the reed and being of such shapeas to leave a small elongated spring extending toward the free end ofsaid reed and within said cutout, a movable contact carried by the freeend of said small spring and adapted to co-operate with the sta-vtionary contact, connections between said contacts and magnetizing coil,whereby upon energization thereof vibration of the armature is effected,an additional contact carried by each arm of the U, on each side of thereed, and symmetrical with respect thereto, said additional contactsbeing disposed opposite a portion of the cutout region in said reed,additional movable contacts carried on opposite sides of said reed forco-operation with said additional stationary contacts, and means forsupporting said additional movable contacts from a portion of the reedoutside of the cutout region.

4. The structure of claim 3, wherein said reed is provided with anadditional cutout region nearer the rigid end thereof and at a pointwhere the reed is free from its support and begins to fiex.

5. A circuit make and break ,device comprising an electro-magnetincluding a winding and a pole piece, a reed supported at one end andadapted to have its free end vibrate in proximity to said pole piece,said end having a rest position, contacts carried by said reed, one ofsaid contacts being resiliently mounted with respect to said reed, andthe remaining being rigidly mounted with respect thereto, a fixedcontact co-operating with said resiliently mounted contact and connectedto the winding of said electro-magnet for controlling the same, and apair of spaced contacts on opposite sides of the remaining reed contactsand adapted to cooperate therewith, said pair of fixed contacts beingresiliently mounted and each having a resonant frequency greater thanthe frequency oi the reed system, so that separation of contacts occursat the point corresponding to the rest position of said reed.

6. A circuit making and breaking device, comprising an. electro-magnethaving a winding and a pole face, a reed supported at one end and havingits other end free to vibrate in proximity to said pole face, said reedhaving a normalidle position eccentric with respect to said pole face, amovable driving contact resiliently mounted and actuated by said reed, afixed contact cooperating therewith for controlling the winding of saidelectro-magnet, said two contacts being closed in the idle position ofsaid reed, an abutment vibrated by said reedand adapted to separate saiddriving contacts upon the attracted movement of said reed, a pair ofcontacts rigidly mounted on said reed, said contacts being disposed onopposite sides thereof, and a pair of spaced contacts, each one of saidspaced contacts co-operating with one of said rigidly mounted contacts,said spaced contacts being resiliently mounted and having a naturalresonant frequency substantially greater than the resonant frequency ofthe reed, so that separation of contacts occurs at the pointcorresponding to the rest position of said reed.

7. The structure of claim 6, wherein said rigidly mounted vibratingcontacts are secured to said reed at a point nearer the fixed end thanthe contacts themselves.

8. In a vibratory motor, the combination of a frame having anenergizable pole piece thereon, and a reed disposed for movementinresponse to energizations of said pole piece and having one end securedto said frame, contact means onsaid reed intermediate its ends, saidreed comprising an elongated resilient memberhaving ian aperture thereinadjacent said one end to cause the free reed to fiex initially adjacentsaid one end, sa-id aperture being non-circular and free of any definitetransverse axis of fiexure to prevent stress concentration,

9. In a vibratory motor, ythe combination of a frame having anenergizable polepieee thereon, and a reed disposed for movement inresponse to energizations of said pole piece and having one end securedto said frame, contact means on said reed intermediate its ends, saidreed comprising an elongated resilient member having an aperture thereinadjacent said one end to cause the free reed to ex initially adjacentsaid one end and having a second aperture therein adjacent said contactto cause the portion beyond said contact means to fiex readily after thecontact means has closed a circuit, said apertures being non-circularand being free of any definite transverse axes of fiexure to preventstress concentration.

10. In a magnetic interrupter a base member, an electromagnet mountedthereon, a vibratory reed member having one end clamped to said base andthe other end free to vibrate under in` fluence vof said electromagnet,a first contact mounted on said reed member, a second contact supportedfrom said base and cooperating with said first contact to open and closea circuit, said reed member having an aperture punched through a.portion thereof,said portion being located solely between said clampedend and said contact, said aperture being non-circular and free of anydefinite -transverse axis of flexure to prevent stress concentration.

11. In a vibrator, the combination of a magnetizable U shaped framehaving arms long in comparison to the bight, a short pole piece carriedby said bight and extending downwardly toward the free ends of saidarms, an elongated spring reed rigidly clamped between the free arm endsand extending toward said pole piece, a small armature rigidly carriedby the free reed end and adapted to oscillate in front of but out.

of contact with said pole piece, said reed having an interior portioncut out below said armature and extending downwardly toward the clampedend for a portion of the reed length, an elongated member rigidlyfastened at one end thereof on a portion of the face of the reed belowthe cut out region but above the rigidly clamped portion, said elongatedmember' extending upwardly toward the armature end of the reed butspaced therefrom so as to enable free relative motion between the reedand the end of said elongated member, a contact secured to the free endof said elongated member on the outer face thereof, a co-operatingcontact therefor and means for mounting said co-operating contact.

12. In a vibrator, the combination of an elongated frame, anelectromagnet mounted at one end thereof and having a core extendingtoward the other end of said frame, a vibratory reed of spring materialrigidly clamped at said other end and extending toward the free end ofsaid core. an varmature of magnetic permeable material secured to thefree end of said reed within the sphere of magnetic influence of saidelectrc magnet, the free end of said reed being adapted to oscillate infront of but out of contact with the free end of said core, said reedhaving an interior portion cut out below said armature and extendingdownwardly toward the clamped end for a portion of the reed length, apair of contact arms rigidly secured at their base to a portion of saidreed below at least the major part of said cut out portion and above theclamped region, said contact arms extending upwardly toward the armatureend of the reed but spaced therefrom so as to enable non-interferingrelative motion between the reed and the ends of said contact arms.contacts secured to the free end of said contact arms on the facethereof, and (zo-operating contacts therefor supported from said frame.

13. In a vibrator, the combination of an elongated frame, anelectromagnet mounted at one end thereof and having a core extendingtoward the other end oi' said frame, a vibratory reed of spring materialrigidly clamped at said other end and extending toward the free end ofsaid core, an armature of magnetic permeable material secured to thefree end of said reed within the sphere of magnetic influence of saidelectromagnet, the free end of said reed being adapted to oscillate infront of but out of contact with the free end of said core, said reedhaving an interior portion cut out below said armature and extendingdownwardly toward the clamped end for a Dortion of the reed length, acontact arm rigidly secured at its base to a portion of the face of saidreed below at least the major part of said cut-out portion and above theclamped region, said contact arm extending upwardly toward the armatureend o1' the reed but spaced therefrom so as to enable non-interferingrelative motion between the reed and the end of said contact arm, acontact secured to the free end of said contact arm on the face thereof,and a co-operating contact therefor supported from said frame.

14. In a vibrator of the class described a reed fixed at one end andweighted at its opposite end for vibration, said reed being relativelystiff at its fixed end and being provided with an aperture ofsubstantial size relative to the area of the reed adjacent its freeweighted end to render said free end of said reed accordingly moreflexible, whereby each interval of contact is prolonged and the contactpressure is rendered more nearly uniform during its period.

15. In a vibrator of the class described a fiat, thin vibrator reed xedat one end `and being relatively stiff, the' other end of said reedbeing provided with narrow depending spaced lingers extending along theside margins of said reed, and a weight secured on the distal ends ofsaid fingers whereby the resiliency and flexibility ol' said reed isincreased at its free end and each interval of contact is'prolonged andcontact pressure is rendered more nearly uniform during its period.

16. In a vibrator, the combination of a base, an electromagnet and reedmounted on said base, said reed having one end thereof clamped and theother end weighted with an armature and being free to vibrate under theinfluence of said electromagnet, at least one contact supported on saidreed at a region near the clamped end with a small reed part extendingto said clamped end and a large reed part extending to said weight, atleast one additional contact supported from said base cooperating withsaid first contact for circuit interruption during reed vibration, saidreed having part of its material cut away for most of said large reedpart length leaving the large reed part free of any definite transverseaxis of fiexure to prevent stress concentration whereby the flexingcharacteristics of said reed are such as to prolong contact closureperiod.

17. The .structure of clairn 16 wherein the reed material cut out liesalong a central zone lengthwise of said reed.

18. In a vibrator, the combination of 'a base, an

electromagnet and reed mounted on said base,

said reed having one end thereof clamped and the other end weighted withan armature and being free to vibrate under the influence of saidelectromagnet, at least one movable contact supported on each side ofsaid reed at a region near the clamped end with ya small reed partextending to said clamped end and a large reed part extending to saidweight, a stationary contact on each side of said reed supported on saidbase cooperating with said movable contacts for circuit interruptionduring'reed vibration, said reed having part of its material cut awayfor most of said large reed part length leaving the large reed part freeof any definite transverse axis of flexure to prevent stressconcentration whereby the iiexing characteristics of said reed are suchas to prolong contact closure periods.

i9. In a vibrator, the combination of a base, an electromagnet and reedmounted on said base, said reed having one end thereof clamped and theother end weighted with an armature and being free to vibrate under theinfluence of said electromagnet, at least one contact supporting armmounted on said reed at a region near the clamped end with a small reedpart extending to said clamped end and a large reed part extending tosaid weight, said arm extending away from said reed and away from theclamped end thereof to permit relative non-interfering motion, a movablecontact sup-ported at the free end of said arm, at least one stationarycontact supported from said base cooperating with the movable Contactfor circuit interruption during reed vibration, said reed having part oits material cut away for most of said large reed part length leavingthe large reed part free of any definite transverse axis of iiexure toprevent stress concentration whereby the flexing characteristics of saidreed prolong contact closure periods.

20. In a vibrator, the combination of a base, an electromagnet and reedmounted on said base, said reed having one end thereof clamped and theother end weighted with an armature and being free to vibrate saidelectromagnet, at least one contact supporting arm rigidly mounted oneach side of said reed at a region near the clamped end with a smallreed part extending to said clamped end under the influence said armsextending away from said reed and away from the clamped end to permitrelative non-interfering motion, a movable contact mounted on the freeend of each arm, contacts teristics of said reed prolong contactclosure4 periods.

2l. The structure of claim 20 wherein the material cut out from the reedis along a central zone.

22. The structure of claim 20 wherein said reed has part of its materialcut away at the small reed part leaving the small vreed part free of anydeflnite transverse axis of fiexure to prevent stress concentration. Y

23. The structure of claim 20 wherein the contacts supported from saidbase are mounted on the free ends of arms with the other ends -of saidarm being supported on said base, and wherein said arms are springssubstantially stiffer than said reed.

24. The structure of claim 20 wherein the reed material cut out .extendsalong a central zone and wherein said contacts supported from said baseare mounted on contact supporting armswith said arms being substantiallystiffer than said reed.

25. In a vibrator, the combination of a base, an electromagnet and r'eedmounted on said base. said reed having one end thereof clamped and theother `efnd weighted with an armature and being free to vibrate underthe influence of said electromagnet, a contact supporting arm rigidlymounted on each side of said reed at a region near the clamped end witha small reed part exnding to said clamped end and a large reed partextending to said weight, said arms extending away from said reed onopposite sides and extending generally toward the weighted end toypermit relative non-interfering motion, a movable contact mounted'onthe free end of each of said arms, a stationary contact for each of saidreed contacts, said stationary contacts being mounted from said base andcooperating with said reed contacts for circuit interruption during reedvibration, said reed having part of its material cut away from theweighted 'end downto said mounting region on said reed leaving thevlarge reed part free of any definite transverse axis of flexure toprevent'stress concentration.

26. The structure of claim 25 wherein said cutout region lies along acentral zone of said reed.

27. The structure of claim 25 wherein said small reed part has a cutouttherein.

28. rlvhe structure of claim 25 wherein said stationary contacts aremounted on the free ends of arms mounted on said base, said arms beingsubstantially stiffer than said reed.

29; A vibrator comprising an elongated magnetizable member, a pole pieceformed in said member, a vibratable reed, having an armature cooperatingwith said pole piece, means for rigidly supporting the end of said reedremote from said armature on said member, a magnetizing coil adapted toinduce a magnetic field in said .member and said reed, a stationarycontact carand a large reed part extending to said weight,

between said contacts and piece, a stationary contact carried by saidmem-y ber, said reed having an elongated cutout inthe vibrating portionthereof, said cutout being of such shape as to leave a smallelongated-spring member integral with said reed, and extending with saidcutout toward the free end of said reed, a contact carried by the freeend of said small spring and adapted to cooperate with said stationarycontact, said contacts being connected with said magnetizing coil, anadditional contact carried by said magnetizable member and an additionalcooperating movable contact carried by said reed at a point outside o!said cutout.

31. In a potential changer adapted for use with a direct current sourceas the B supplyoi an automobile radio, an article of manufactureconsisting of a mechanical interrupter unit comprising a U-shaped baseof magnetic permeable material, a magnetic coil positioned between thearms of said base, a core for said coil having one end thereof securedto said base and the other end thereof facing toward the ends of thearms with said stationary conof said base, a vibratory reed o magneticpermeable material mounted between the arms of said base and having thefree end thereof extending toward the last-mentioned end of said corewith the major portion of the body' thereof disposed substantiallyparallel to the axis of said core, the free end of said vibratory reedthereby constituting one pole of said magnetic coil, an opening cut inthe body of said reed and a tongue on said reed and disposed in saidopening. a contact mounted on said tongue and a cooperating contactsupported independently of said reed and adapted to cooperate with saidtongue contact.

32. AS an article of manufacture, a mechanical interrupter comprising anelongated base of magnetic permeable material, a magnetic coil having acore with one end mounted on one end of said base and the other endfacing toward the other end of said base, an elongated vibratory reedmounted on the last-mentioned end of said base with the major portion ofthe body thereof disposed substantially parallel to the axis of saidcore and the free end thereof disposed adjacent to and offset from thelast-mentioned end of said core to constitute one pole of said magneticcoil. an opening cut in the body of said reed and a tongue on saidreed'and disposed in said opening, a contact mounted on said tongue anda cooperating contact supported independently of said reed and adaptedto cooperate with said tongue contact.

HENRY M. DRESSEL. KENNETH C. ALLISON. EDWARD J. MASTNEY.

